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the fact that hereby likewise favourable and injurious influences of 
continued fore-heating would appear side by side. 
Could the favourable influence be eliminated we should, in accordance 
with this view, by our observations, already below 45° have found 
four different curves for the four different periods of fore-heating, 
and the zero-curve calculated herefrom or found by extrapolation, 
would have answered vaN ’t Horr’s rule. That we now only found 
one single curve might be explained by the circumstance that here 
the favouring influence annuls the noxious. Now it is in itself already 
an adventurous supposition, that at the 4 different periods of fore- 
heating those two influences always annul each other, but its possibility 
is not excluded. However, the fact should be emphatically pointed 
out that a Jdasting noxious action on the yeast at those tempe- 
ratures at which the curve is simple was not observed during the 
time of our experiments: when the yeast, after being heated for 
20 minutes at 45° C., was cooled to 20’ C., it showed the same 
fermentation velocity as if no heating had taken place. Yet, in order 
to accept BrLACKMAN’s theory, it should be admitted that at the fore- 
heating + 35°/, of the yeast had lost its activity. 
Now, here again an outlet might be found by introducing a second 
new hypothesis. It might be admitted that the inactivation of the 
fermentation function had taken place “invertibly’, but then it must 
also be admitted that for the inactivation at temperatures at which 
the single optimum curve must be replaced by many, an uninvertible 
annihilation exists together with the invertible inactivation. Moreover, 
then still the fact remained to explain that the 4 optimum curves 
for the time O, which we calculated from the different curves observed 
at noxious temperatures, only taking the “lasting” noxious action, 
into account, fall together into one. Neither this is to be conceived 
without the help of a third hypothesis, for, if this holds good for 
the 4 zero-curves found after Rureers’ calculation this will not in 
general be so with the curves calculated after our method. 
These three new hypotheses should moreover not only be accepted 
as valid for the alcohol fermentation, but also for the inversion 
action of cane sugar. 
Let us now consider the fundamental assumption whereon this part 
of Rereers’ opposition is based. After his view a favourable influence 
increasing with the time of fore-heating might also in our experiments 
have been of some weight. 
We think, however, the motives for this conception insufficient. 
For it reposes in the first place on a conclusion derived by this 
experimenter from modifications stated in the praesentation time for 
